If you’re looking for a way to check or remove an IP from the SORBS DUHL blacklist, there’s good news: SORBS no longer exists as an active blocklist. Proofpoint decommissioned the service on June 5th, 2024, and its DNSBL zones no longer provide reputation data.

That means there’s no SORBS DUHL listing to remove today. If an old bounce message, blacklist checker, or article says your IP is listed, the information is outdated. What still matters is why an IP might have appeared on DUHL in the first place and whether your current sending setup could cause problems with active blocklists.

Is SORBS DUHL still active?

SORBS DUHL has been inactive since June 5th, 2024, when Proofpoint shut down SORBS. The service no longer provides reputation data, so IP addresses can no longer be actively listed or delisted through DUHL.

You may still find SORBS in older blacklist-checking tools, bounce messages, and deliverability articles. Treat those references as legacy information rather than evidence of a current SORBS listing.

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What was the SORBS DUHL blacklist?

SORBS stood for Spam and Open Relay Blocking System, a DNS-based blocklist that operated from 2001 until 2024. DUHL, or the Dynamic User and Host List, was one of several lists maintained by SORBS.

DUHL identified IP addresses and ranges believed to be dynamically assigned to end users, including addresses associated with broadband, dial-up, cable, and wireless connections. These IPs generally weren’t expected to send email directly to receiving mail servers.

An IP could therefore appear on DUHL without having sent spam. SORBS used information including reverse DNS records and network data to identify dynamically assigned ranges. 

A listing indicated that the IP appeared to belong to a dynamic pool, not necessarily that its owner had engaged in abusive email activity.

Why dynamic IPs still matter for email

SORBS DUHL may be gone, but sending email directly from a dynamic IP can still cause deliverability problems. Dynamic addresses can change between users and often have generic or missing reverse DNS records, which makes it difficult for receiving servers to establish a reliable sending reputation.

If you send email from your own infrastructure, use a properly configured static IP with valid reverse DNS. For most senders, using a reputable email service provider is the simpler option.

What should you do if SORBS still shows your IP as listed?

You don’t need to request delisting from SORBS DUHL. The service has been decommissioned, so there is no active list or delisting process.

If a blacklist checker still reports a SORBS listing, check when its data was last updated. Older tools may continue to display historical SORBS results even though the underlying service is no longer operating.

Instead, check your IP against currently maintained blocklists and confirm any reported listing directly with the organization that operates the list. Spamhaus, Barracuda, SpamCop, and SpamRATS are among the blocklists still in use.

It’s also worth checking your reputation with the major mailbox providers themselves. Gmail and Outlook use their own reputation and filtering systems, so a clean result from third-party blocklists doesn’t automatically mean your messages will reach the inbox.

How to keep your IP and domain off active blocklists

A SORBS DUHL listing is no longer something you need to worry about, but the sending practices that protect your reputation still matter.

  • Set up SPF, DKIM, and DMARC: Email authentication gives receiving servers a way to verify that messages using your domain are legitimate.
  • Increase sending volume gradually: New domains and IPs need time to establish a sending reputation.
  • Keep your email list clean: Remove invalid addresses and avoid purchased lists that may contain spam traps with a service like EmailListVerify.
  • Send email only to people who expect it. Clear opt-ins and simple unsubscribe options reduce spam complaints.
  • Monitor your sender reputation. Watch bounce and complaint rates, use provider tools such as Google Postmaster Tools or Warmup Inbox, and investigate unusual changes early.

FAQ

Is SORBS still working in 2026?

No. Proofpoint decommissioned SORBS on June 5th, 2024, and its DNSBL zones no longer provide reputation data. SORBS DUHL is therefore no longer an active blocklist.

Why does a blacklist checker still show SORBS?

Some blacklist checkers still contain references to SORBS even though the service has shut down. This may be legacy or cached information. Check your IP against actively maintained blocklists and verify any listing with the organization that operates the list.

How do I remove my IP from SORBS DUHL?

You don’t need to. SORBS DUHL no longer operates, so there is no active listing to remove or delisting request to submit. If you’re experiencing email deliverability problems, check your IP against active blocklists and investigate your current sender reputation instead.

What replaced SORBS?

There is no direct replacement for SORBS. Several other DNS-based blocklists remain active, including Spamhaus, Barracuda, SpamCop, and SpamRATS. Different email providers also use their own reputation systems when deciding whether to accept or filter messages.

What is a dynamic IP and why does it matter for email?

A dynamic IP is an address that can change over time or be reassigned to different users. Sending mail directly from one can raise reputation concerns because receiving servers can’t reliably associate the address with a consistent sender. A static IP or reputable email service provider is generally better suited to sending email.